Hebrews 10:5

When he cometh into the world

(εισερχομενος εις τον κοσμον). Reference to the Incarnation of Christ who is represented as quoting Psalms 40:7-9 which is quoted. The text of the LXX is followed in the main which differs from the Hebrew chiefly in having σωμα (body) rather than ωτια (ears). The LXX translation has not altered the sense of the Psalm, "that there was a sacrifice which answered to the will of God as no animal sacrifice could" (Moffatt). So the writer of Hebrews "argues that the Son's offering of himself is the true and final offering for sin, because it is the sacrifice, which, according to prophecy, God desired to be made" (Davidson).A body didst thou prepare for me

(σωμα κατηρτισω μο). First aorist middle indicative second person singular of καταρτιζω, to make ready, equip. Using σωμα (body) for ωτια (ears) does not change the sense, for the ears were the point of contact with God's will.